Electric connector for corona discharge devices



y 4, 1948- E. B. NICHOLS, 2,440,828

ELECTRIC CONNECTOR FOR CORONA DISCHARGE DEVICES Filed April 13, 1944 IN VEN TOR.

Edgar B. M'cfiolr Patented May 4, 1948 UNITED STATES PATENT OFFICE ELECTRIC CONNECTOR FOR CORONA DISCHARGE DEVICES This invention relates to electrical connectors, and it has particular relation to connectors suit- --able for use at high voltages, the present application being a substitution in part for my prior abandoned application, Ser. No. 449,219,-flled July 1, 1942.

There are various types of electrical apparatus which are operated at high voltages. At these voltages, it is not unusual for corona discharges to take place which very greatly shorten the life of connectors employed to connect such apparatus to other apparatus. This is due in many instances, among other things, to rough or sharp surfaces on the connectors along which the electron streams are highly concentrated, or to constructions which do not permit sufliciently tight or firm connection with terminal elements of the apparatus, and to other similar causes.

The principal object of my present invention is to provide an improved terminal connector for an an improved electrical terminal connector which will grip the terminal elements very firmly and tightly.

Another object of my invention is to provide an improved electrical terminal connector which is self contained and therefore requires no external supporting means for the purpose of a mounting.

Another object of my invention is to provide an improved terminal connector which readily lends itself to use in places to which access is difficult.

Another object of my invention is to provide an improved terminal connector which will readily dissipate the heat developed therein at high operating voltages.

Another object of my invention is to provide an improved terminal connector which is comprised of a minimum number of parts, is simple in construction, and highly efficient in use.

I accomplish the aforementioned and other ancillary objects by providing a spherical or ballshaped clamping member which has a dlametric bore terminating in a conical seat at one end. Into this bore is placed a tubular collet formed with a conical head at one end which cooperates with the conical seat in the clamping member. When the bore of the collet is slipped over a ter minal element and the head of the collet is drawn down firmly against the conical seat, its Jaws tightly grip the terminal element. Due to the smooth surface of the spherical clamping memher, no sharp edges, points or other similar surfaces are present On which electron streams can concentrate. Therefore, my improved connector is free from corona discharges and from the inherent disadvantages resulting therefrom.

The invention is susceptible of a variety of forms. Its advantages, and other inherent objects thereof, will be readily understood, however, from the following description of several different forms when read in connection with the accompanying drawing in which Figure 1 is a view partly in elevation and partly in section showing one form of my invention,

Figure 2 is a perspective view of the collet,

Figure 3 is a view partly in elevation and partly in section of a clamping member formed according to another embodiment of my invention,

Figure 4 is an enlarged, fragmentary perspective view of a portion of the clamping member shown in Figure 3,

5 Figure 5 is a view similar to Figure 1 showing still another and preferred form of my invention,

Figure 6 is a side elevation of the collet used in the form of the invention shown in Figure 5, and

Figure '7 is an elevation of a slightly modified form of the invention shown in Figure 5.

Referring to the drawing in greater detail, Figure 1 shows a terminal connector having a clamping member H] which has a smooth, continuous surface in all directions so as to provide no sharp, pointed or rough edges. The member I0 may be of any suitable shape, such as a sphere, an ellipsold, or any other similar surface of revolution, the shape shown being that of a sphere for the sake of illustration. The member I0 is formed with a diametric bore I I terminating at one end in an outwardly diverging seat 12, such as a, cone or the like.

Within the bore H is fitted a collet [3 having a central bore l4 and provided with threads l5 at one end. The other end of the collet terminates in a head I6 shaped exteriorly to conform to the shape of the seat 12, being conical in this instance. The head i6 is split radially outwardly from the bore M by a plurality of circumferentially distributed, longitudinally extending slits H. The slits ll divide the head I6 into a number of jaws which, when forced together, firm-1y grip a terminal element 18, such as a prong of a radio tube, for example. previously received within the bore of the collet. I

The collet i2 is appreciably longer than the diameter of the clamping member ID. Thus, when the collet is inserted into the bore Ii, its threaded end extends beyond the-member id, as clearly seen in Figure 1. A knurled nut I! is threaded, on the threads I! and bears against the member In. As the nut I9 is advanced on the collet l3, it is obvious that it will draw the head It of the collet tightly into seating engagement with the seat 12. The seat, in turn, forces together the Jaws of the collet head i! to cause these Jaws to firmly grip the terminal element I8.

When applied to apparatus which operates at high voltages, as in the case of radio transmitter tubes, for example, considerable heat may be developed in the connector. To provide a construction in which the heat will be rapidly dissipated, the clamping member ID may be formed with a plurality of slots, as shown in Figure 3. One set of slots 20 may extend circumferentially around the member In in parallel relation and for a substantial depth toward the bore ll.

Another set of slots 2! may extend in planes at right angles to the slots 20 and may be of the] same or difierent depth, as found suitable. While the-slots 2! may also be parallel to each other,

, if desired, they are shown, by way of illustration,

as lying in planes which intersect each other at the diameter of the member I which constitutes the axis of the bore II. In any case, a plurality of sector-like, radially outwardly extending, spaced fins 22 are thus formed which have a total area sufilcient to rapidly dissipate the heat developed in the connector at'high operating voltages. To eliminate sharp edges on the fins 22 formed by the intersecting slots 20 and 2i, which normally invite corona discharges at high voltages. the edges 23 thereof are preferably rounded off. In this way, a condition normally conducive to corona discharges is eliminated. L

In certain instances, the terminal element i8 may be in such a location that it is dimcult to reach it with the fingers. For such instances, the clamping member Ill may be formed with a'radial or other suitably arranged bore 24 constituting a socket for the reception of a removable handle or other suitable tool 25. By means of the handle 25, application of the connector to terminal elements in places normally hard to reach is made easy.

are usually satisfactory at moderately high voltages. At very high voltages, however, it may be found that the knurled nut i9 or the fins 22 occasionally tend to invite a corona discharge. To avoid this, I preferably form the connector in the manner illustrated in Figures and 7. In this form of my invention, the connector is made in two complemental parts which, together, form a sphere or other suitable surface of revolution, the form shown in Figure 5 comprising two, cooperating, hemispherical parts 26 and 21 formed with aligned bores 28 and 29. The bore 28 is formed with the seat l2 and the lower end of they bore 29 is threaded for cooperation with the threads I 5 of the collet. After inserting the collet l3 into the bore 28, the part 21 of the connector is threaded onto the threads l5 and tightened against the part 26. This draws the collet head 16 into firm seating engagement with the seat 12 to cause the jaws of the collet head to firmly grip the terminal element. A flat 30 on the The forms of my invention thus far described and 21, or 2612 and 4 shank of the collet cooperates with a similar flat in connector part 2. to prevent the collet from turning as the connector against the Part 2|.

The modification of Figure 7 is similar 'to that of Figure 6 except that the connector part 28:; is formed of a spherical'segment which is larger than ahemisphere and the cooperating part 21a is formed of a spherical segment which is smaller than a hemisphere. In either case, the parts 28 21a together form a sphere or ball having a continuous smooth surface in all. directions and devoid of portions which tend to invite a corona discharge even at extremely high operating voltages.

From the preceding description, it is apparent that I have provided an improved terminal connector'having many inherent advantages. Not

- only does the smooth, continuous surface of the spherical or other similar clamping member avoid the likelihood of a corona discharge with the attendant dangers, but also, the terminal element is firmly gripped by the jaws of the collet head it to provide a tight connection. A flexible or other suitable lead 2| may be inserted through the end of the collet is opposite the head it and permanently secured in place 'within'the bore thereof, as by solder, to provide a connecting lead to other apparatus or devices. It will also be apparent that my improved connector needs no supporting panels, terminal plates, or other devices to support it and that it can be applied directly to many types of terminal elements.

Having described my invention in considerable detail, I claim:

1. In a self contained clamping member having a smooth, continuous surface in all directions and provided with a bore terminating at one end in an outwardly diverging seat, a collet fitted in said bore, said collet also having a bore therethrough and including a head shaped exteriorly similarly to said seat, said head being split radially outwardly from said last named bore and being adapted to receive a terminal element, and means including a portion clear through the bore in said first named part and into the bore of the other of said parts, and characterized still further in that said'other part is threadedly received on said collet for coaction with said first named part to draw said collet head tightly against said seat.

2. In a self contained electrical connector, a-

ciamping member comprisinga pair of complementary parts which together constitute a geometric figure having a smooth, continuous surface in all directions, said parts having aligned bores therethrough, the bore of terminating at its outer end in an outwardly diverging seat, and a ,collet fitted into said bores. said collet extending clear through the bore in said one part and into the bore in the other of said parts, said collet also having a bore therethrough and including a head shaped exteriorly similarly to said seat, said head being split radially outwardly from said lastnamed bore and being adapted to receive a terminal element, said part 21 is tightened electrical connector, 9.

one of said parts terminal element.

3. An electrical connector according to claim 2 wherein said clamping member parts together constitute a sphere.

EDGAR B. NICHOLS.

REFERENCES CITED The following references are of record in the [lie of this patent:

Number Number UNITED STATES PATENTS Name Date Higgins Aug. 9, 1887 McWiiliams May 6, 1913 Lansing Mar. 19, 1935 Casey Apr. 16, 1935 Trees Sept. 12, 1944 FOREIGN PATENTS Country Date Great Britain 1913 Sweden Oct. 28, 1930 Austria Jan. 23, 1923 

